1. Field of the Invention
This invention relates to a method of and a system for entering identification codes into a vehicle antitheft system.
2. Description of Related Art
In order to cope with frequent occurrence of vehicle thefts in recent years, various antitheft devices and systems have been proposed. One of the antitheft systems is called an immobilizing system comprising an identification code dispatching key and an immobilizer unit which monitors an identification code (which is hereafter referred to as an ID code) dispatched from the key to prevent an engine controlling unit (EGI) from actuating the engine when an ignition switch is turned on in the event that the key is identified as incorrect based on the ID code. Such an antitheft system is known from, for example, Japanese patent application No. 6-181146, filed on Aug. 2, 1994, by the applicant of this application and now opened to the public as Japanese Unexamined Patent Publication No. 8-40206.
Another type antitheft system employs encoded words (which are hereafter referred to as CWs) for permitting the engine controlling unit (EGI) to actuate the engine as is known from, for example, Japanese patent application No. 6-297086, filed on Nov. 30, 1994, by the applicant of this application and opened to the public as Japanese Unexamined Patent Publication No. 8-150899. Specifically, the immobilizer unit compares an ID code of a key read in through a transponder with an ID code registered therein and transfers a word code, different in form from these ID codes, to the engine controlling unit (EGI) whenever verifying the coincidence between these ID codes for another verification of the coincidence between the word code from the immobilizer unit and a word code registered in the engine controlling unit (EGI). The immobilizer unit transfers a permission command signal to the engine controlling unit (EGI) to permit it to actuate the engine only when the engine controlling unit (EGI) verifies the coincidence between these encode words.
In the event where the immobilizer unit and/or the engine controlling unit (EGI) of this type of vehicle antitheft system are replaced with new ones at a factory or a service shop, which is accompanied by entering ID codes and word codes in these new immobilizer unit and engine controlling unit (EGI), the utilization is made of a special testing device to coercively put the engine controlling unit (EGI) in a state of engine actuation. Such an ID code and encoded word entry device is known from, for example, Japanese patent application No. 6-324472, filed on Dec. 27, 1994, by the applicant of this application and now opened to the public as Japanese Unexamined Patent Publication No. 8-180226.
Prior art vehicle antitheft systems are somewhat troublesome in the entry of ID code and encoded words into immobilizer units and engine controlling unit (EGI) and have a need to be assisted by a code entry device.